Knockout roses give gardeners a no-fuss approach to growing roses, since deadheading is not needed. The cherry-colored blossoms display from summer into fall. Knockout is a disease-resistant shrub that can reach a height and width of 6 feet if not pruned. Introduced in the United States in 2000 by the Conard-Pyle company, knockout is cold hardy to USDA zone 4 and heat hardy to USDA zone 9. Plant knockout roses along the foundation or walkway, or as groupings in a landscape island for a colorful focal point.
Choose a well-drained and full-sun location to plant knockout roses. Add 1 to 2 feet of space between the expected width of the full grown shrub and other shrubs or structures, like a house, for air circulation.
Dig the hole as deep as the container is tall and twice as wide.
Mix about 25 percent organic matter–like leaf mold, compost or peat moss–into the removed soil.
Remove the knockout rose from the container and place it in the center of the hole. The graft (a bulge on the main stem) should be about 1 inch above ground level in the south, including USDA zones 6 or higher, and about 1 inch below ground level in the colder USDA zones, including 5 or lower. Adjust the amount of soil in the bottom of the hole if necessary.
Backfill the hole halfway with amended soil. Water around the shrub to settle the soil and then finish backfilling the hole.
Apply 2 to 3 inches of mulch, like pine chips, around the knockout rose shrub, keeping the mulch about 3 inches from the stem of the plant.
Water every seven to 10 days if there is no rainfall.